Write a Program for a Singleton Class

Replies

• 

  Sahithi Pallavi

  #-Link-Snipped-# - No idea. Explanation please.
  
  PS : Sorry for bumping the old thread but I want answer.
• 

  Anoop Kumar

  Singleton model: Only one thread can access to the object. Unless and until it completed it's operation of that object other thread have to wait.
  -------
  In above example #-Link-Snipped-# wrote is actually synchronizing the static method since static variable is shared by all the object the whole class is now synchronized. Other way is to use synchronize all methods (if no static block is there.)
  -------------------------
  Simplest example is to create a servlet and add following code to your doPost/doGet
  

  for(int i=0;i<10;i++){
  system.out.println(i);
  Thread.sleep(1000);
  }

  now add following class signature to your servlet
  

  public class YourServlet extends HttpServlet
  implements SingleThreadModel {
  /*Your Code , (Try making variable as class member and removing/ adding SingleThreadModel  )*/
  }

  try requesting servlet from different tab/window you will see that other request have to wait until a request from one tab not completed.
  Since container only create only one object of servlet to serve the application no matter how many request are coming.
  ----------------------
  edit: Core java example
  
  

  class TestSynchronized  extends Thread {
     
      private  String ThreadName;
     
      TestSynchronized(String param){
          this.ThreadName=param;
      }
      public void run() {
          try {
              aMethod(ThreadName);
          } catch (InterruptedException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
          }
         
      }
      static synchronized void aMethod(String s) throws InterruptedException{
          int i=0;
          System.out.println("ThreadName  "+s);
          while(i<10){
              System.out.println(i);
              Thread.sleep(1000);
              i++;
          }
         
         
      }
   
  }
   
  public class SynchronisedClass {
      public static void main(String []args){
        TestSynchronized t1 = new TestSynchronized("t1");   
        t1.start();
        TestSynchronized t2 = new TestSynchronized("t2");   
        t2.start();
      }
     
  }